matlab连接的矩阵尺寸不一致

Question

here is my code:

C=@(k) [k,k,2.*k;3,2.*k,5;1,k,k];

AV=@(k,t) [3*t, 6, 9]*C(k)*[3*t ;6 ;9];

avaint=@(k,a,b) quadgk(@(k) AV(k,t),a,b);

AVAR=@(t) avaint(t,0,87600);

Is shows:

Error using vertcat
Dimensions of matrices being concatenated are not consistent.

when I want to print AVAR(3)

Answer 1

Source of Error

The quadgk function passes a vector of integration points to the function handle given to it. From the documentation :

The function y = fun(x) should accept a vector argument x and return a vector result y, where y is the integrand evaluated at each element of x.

This creates the dimension mismatch causing the error.

Solutions

To get around this implementation, you can perform the numerical integration using the integral function with the ( 'ArrayValued' , true ) option pair:

avaint = @(t,a,b) integral(@(k) AV(k,t),a,b,'ArrayValued',true);

Or, you can use arrayfun within AV to abide by the requirement of quadgk :

AV = @(k,t) arrayfun(@(k_el) [3*t, 6, 9]*(C(k_el)*[3*t ;6 ;9]),k);